Millions of South Africans have turned out to vote in the country's first election since the death of Nelson Mandela.

The poll marks 20 years since South Africa's first democratic election following almost five decades of apartheid rule.

Counting has begun but there is little doubt about the result, with the African National Congress (ANC) widely expected to retain power, albeit it with a much smaller margin than in previous elections.

Voters young and old wrapped up against the early winter chill to stand in long lines across the country, evoking memories of the huge queues that snaked through streets and fields for South Africa's historic all-race elections in 1994.

"It is great voting for the first time. Now I have a say in the country's election and what is happening. It is something new in my life," said 18-year-old Mawande Nkoyi.

Chief election commissioner Pansy Tlakula said the turnout was "extremely high" at the 22,263 polling stations.

As many as 25 million people cast their vote in what was a largely peaceful election, but protests in Gauteng, Limpopo and in the western and eastern cape provinces did turn some voters away.

Polls put ANC support near 65 per cent, only a shade lower than the 65.9 per cent it won in the 2009 election that brought president Jacob Zuma to power.

The ANC's enduring popularity has surprised analysts who had said the party could suffer as its glorious past recedes into history and voters focus instead on the sluggish economic growth and slew of scandals that have typified Mr Zuma's first term.

South African election facts

Voters elect a political party, rather than individual candidates.

The lawmakers then elect the president from the party which garners the most votes.

25.39 million South Africans, almost half of the population, registered to vote.

There are 8,652 candidates from 45 political parties, but only 29 parties are contesting.

Final results must be released within seven days.

Africa's most sophisticated economy has struggled to recover from a 2009 recession - its first since 1994 - and the ANC's efforts to stimulate growth and tackle 25 per cent unemployment have been hampered by powerful unions.

South Africa's top anti-graft agency accused Mr Zuma this year of "benefiting unduly" from a $24 million state-funded security upgrade to his private home at Nkandla in rural KwaZulu-Natal province that included a swimming pool and chicken run.

Mr Zuma has denied any wrongdoing and defended the upgrades as necessary for the protection of a head of state. He confidently told reporters earlier this week the Nkandla controversy was "not an issue with the voters".

His personal approval ratings have dipped this year, but Mr Zuma appeared relaxed and assured as he voted at a school near Nkandla, ending what he called a "very challenging" campaign.

"I hope that all voters will cast their votes free," he said. "This is our right that we fought for."

Election 'reassuringly boring': economist

Besides being easy fodder for cartoonists who have revelled in the freedom of speech enshrined in the post-apartheid constitution, Nkandla has exposed the gulf between current and former ANC leaders, in particular Nelson Mandela, South Africa's first black president.

It has also become the rallying cry for those who feel the ANC's dominance, as it enters its third decade in power, has damaged the soul of the 102-year-old former liberation movement.

"It is not necessarily the huge sum paid by the public that is the most corrupt aspect of Zuma's palatial rural estate," the Business Day newspaper said in an editorial this week.

"It is how voraciously this wretched business has sucked in so many others: ministers, bureaucrats, party officials and, as the election hots up, ordinary loyalists."

Barring a major upset, the stock market and the local currency should take the vote in their stride and could even gain if South Africa's reputation for stability relative to other emerging markets such as Brazil, Ukraine or Turkey is affirmed.

"Overall, the election is reassuringly boring," said Simon Freemantle, an economist at Standard Bank in Johannesburg.

"We know who's going to win and we know there are not going to be any radical policy changes. That is reassuring."

South Africa's 'Chavez' leads spirited challenge

The ANC's nearest rival, the Democratic Alliance, polled 16.7 per cent nationwide in 2009 and, even though it has been gaining ground, is still seen too much as the political home of privileged whites to have mass appeal.

Instead, the most spirited challenge has come from the ultra-leftist Economic Freedom Fighters (EFF) led by expelled ANC Youth League leader Julius Malema, who models himself on Venezuela's Hugo Chavez, right down to the jaunty red beret.

In his final rally at a Pretoria soccer stadium, Mr Malema, who wants to nationalise banks and mines and seize white-owned farms without compensation, lambasted everything from the Nkandla issue to foreign investors and former colonial powers.

"London must know that we're not scared of the queen," he said to thunderous applause. "We shall not report to London. We will report to the people. The people of South Africa will decide how business is conducted in South Africa. We are taking everything."

However, even the EFF's noisy emergence is likely to have minimal overall impact, with polls putting its support between 4 and 5 per cent.

The silver-tongued Mr Malema himself is also likely to be barred from public office this month if a court confirms a provisional sequestration order imposed in February because of 16 million rand ($1.5 million) owed in unpaid taxes.

You have no doubt been hearing a lot about the Paris Agreement and know that it pertains to climate change, but are too embarrassed at this stage to ask for an overall explanation of what it's all about.